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Papers by Jacques Malchaire

INDUSTRIAL HEALTH, 2017

This is an open-access article distributed under the terms of the Creative Commons Attribution No... more This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (by-nc-nd) License.

Scandinavian Journal of Work, Environment & Health, 1991

A study wasmade of work conditionssuspected of beingresponsible for a greater prevalence of muscu... more A study wasmade of work conditionssuspected of beingresponsible for a greater prevalence of musculoskeletal disordersamong 33 bricklayers. A standardized questionnaire was used to confirm a high 12-month prevalence of 73 "70 for the low back and about 20 % for the upper limbs. Physical work load was studied with the use of heart rate recordings and posture analyses.According to the heart rate data, the work load was "moderately heavy" (300W). A diagnostic analysis identified work postures that could be considered as imposing a heavy strain on the musculoskeletal system. The risk associatedwith these postures was investigated with biomechanical models.This analysisprocedure made possibleelaborateergonomicsolutions that reduced the work load in general and the biomechanical constraints in particular.

The data collected by the authors in four experimental series have been analysed together with da... more The data collected by the authors in four experimental series have been analysed together with data from the literature, to study the relationship between mean skin temperature and climatic parameters, subject metabolic rate and clothing insulation. The subjects involved in the various studies were young male subjects, unacclimatized to heat. The range of conditions examined involved mean skin temperatures between 33‡ C and 38‡ C, air temperatures (Ta) between 23‡ C and 50‡ C, ambient water vapour pressures (Pa) between 1 and 4.8 kPa, air velocities (Va) between 0.2 and 0.9 m · s−1, metabolic rates (M) between 50 and 270 W · m−2, and Clo values between 0.1 and 0.6. In 95% of the data, mean radiant temperature was within ±3‡ C of air temperature. Based on 190 data averaged over individual values, the following equation was derived by a multiple linear regression technique: ¯Tsk=30.0+0.138Ta+0.254Pa−0.57Va+1.28 · 10−3 M−0.553 Clo. This equation was used to predict mean skin temperature from 629 individual data. The difference between observed and predicted values was within ±0.6‡ C in 70% of the cases and within ±1‡ C in 90% of the cases. It is concluded that the proposed formula may be used to predict mean skin temperature with satisfactory accuracy in nude to lightly clad subjects exposed to warm ambient conditions with no significant radiant heat load.

American Journal of Industrial Medicine, 1985

Journal of Occupational and Environmental Medicine, 1983

Annals of Occupational Hygiene, 1991

Annals of Occupational Hygiene, 2001

Eight laboratories participated in a concerted research project on the assessment of hot working ... more Eight laboratories participated in a concerted research project on the assessment of hot working conditions. The objectives were, among others, to co-ordinate the work of the main European research teams in the field of thermal factors and to improve the methods available to assess the risks of heat disorders at the workplace, and in particular the "Required Sweat Rate" model as presented in International Standard ISO 7933 Standard (1989). The scientific bases of this standard were thoroughly reviewed and a revised model, called "Predicted Heat Strain" (PHS), was developed. This model was then used to predict the minute by minute sweat rates and rectal temperatures during 909 laboratory and field experiments collected from the partners. The Pearson correlation coefficients between observed and predicted values were equal to 0.76 and 0.66 for laboratory experiments and 0.74 and 0.59 for field experiments, respectively, for the sweat rates and the rectal temperatures. The change in sweat rate with time was predicted more accurately by the PHS model than by the required sweat rate model. This suggests that the PHS model would provide an improved basis upon which to determine allowable exposure times from the predicted heat strain in terms of dehydration and increased core temperature.

European Journal of Applied Physiology, 2000

The prediction of the mean skin temperature used for the Required Sweat Rate index was criticised... more The prediction of the mean skin temperature used for the Required Sweat Rate index was criticised for not being valid in conditions with high radiation and high humidity. Based on a large database provided by 9 institutes, 1999 data points obtained using steady-state conditions, from 1399 experiments and involving 377 male subjects, were used for the development of a new prediction model. The observed mean skin temperatures ranged from 30.7 °C to 38.6 °C. Experimental conditions included air temperatures (T a) between 20 and 55 °C, mean radiant temperatures (T r) up to 145 °C, partial vapour pressures (P a) from 0.2 to 5.3 kPa, air velocities (v a) between 0.1 and 2 m/s, and metabolic rates (M) from 102 to 620 W. Rectal temperature (T re) was included in the models to increase the accuracy of prediction. Separate models were derived for nude (clothing insulation, Icl, ≤0.2 clo, where 1 clo=0.155 m2 · °C · W−1, which is equivalent to the thermal insulation of clothing necessary to maintain a resting subject in comfort in a normally ventilated room, air movement=10 cm/s, at a temperature of 21 °C and a humidity of less than 50%) and clothed (0.6 ≤ Icl ≤ 1.0 clo) subjects using a multiple linear regression technique with re-sampling (non-parametric bootstrap). The following expressions were obtained for nude and clothed subjects, respectively: T sk=7.19 + 0.064T a + 0.061T r + 0.198P a− 0.348v a + 0.616T re and T sk=12.17 + 0.020T a + 0.044T r + 0.194P a − 0.253v a + 0.0029M + 0.513T re. For the nude and clothed subjects, 83.3% and 81.8%, respectively, of the predicted skin temperatures were within the range of ±1 °C of the observed skin temperatures. It is concluded that the proposed models for the prediction of the mean skin temperature are valid for a wide range of warm and hot ambient conditions in steady-state conditions, including those of high radiation and high humidity.

Annals of Occupational Hygiene, 1997

International Archives of Occupational and Environmental Health, 1998

Objective: The aim of the present study was to quantify the sensory and functional effects result... more Objective: The aim of the present study was to quantify the sensory and functional effects resulting from a short-duration (30 min) exposure to hand-arm vibration. Subjects and methods: Nine subjects went through nine laboratory experiments. For 32 min they grasped a handle vibrating at three different amplitudes (5, 20, and 80 ms−2) and at three frequencies (31.5, 125, and 500 Hz). Additionally, a reference experiment was conducted in which the handle did not vibrate. Three sensory tests [vibration perception threshold (VPT), pressure perception threshold (PPT), and distal sensory latency time (DSL)], two functional tests [Purdue pegboard (PPB) and maximal voluntary force (MVF)], and a questionnaire concerning the perceived paresthesia and numbness were completed before, during, and after exposure. Results: A 32-min period of exposure to vibration leads to a temporary threshold shift (TTS) of the VPT and to the development of paresthesia and numbness. The VPT appears to vary with the exposure duration according to a first-order model with a time constant about equal to 3 min. The TTS increases with the vibration acceleration amplitude and is greater for an exposure frequency of 125 Hz than for that of 31.5 or 500 Hz. It is also greater at the test frequency 125 Hz than at 31.5 Hz. The other tests do not demonstrate any significant variation. In particular, the PPB test does not demonstrate any loss of dexterity. Conclusion: After some 30 min of exposure to vibration the VPTs are increased and paresthesia and numbness develop. However, these do not appear to influence significantly the capacity or performance at work.

Annals of Occupational Hygiene, 1996

This study investigates the effects of the main characteristics of the working condition on the v... more This study investigates the effects of the main characteristics of the working condition on the vibration exposure on fork-lift trucks. Four hundred and eighty recordings were made on five trucks equipped with four different types of tyres and a 'normal' or an 'anti-vibration' seat, driven while empty or loaded, on a smooth or a rough track by three workers. An analysis of variance was performed to study the main effects and the significant interactions between these factors. A mathematical model is proposed for the weighted acceleration on the floor and on the seat in the vertical axis. This shows quantitatively that the vibration exposure is mainly influenced by the roughness of the track, the speed and the quality of the seat. Inflated tyres are preferable when an anti-vibration seat with a very low resonance frequency is used. In other cases, cushion tyres are more indicated.

British Journal of Haematology, 1980